The present invention relates to a small size or small power electric motor which has a housing provided with an opening and closed by a bearing shield having a guiding for commutator brushes of a commutator device.
Electric motors of the above mentioned general type are known in the art. In the known electric motors the brush holders which receive the commutator or carbon brushes are arranged in isolating fashion on a brush supporting plate which in turn is mounted on the motor housing. It has been shown that when such small size motors are designed with enclosure so that the motor interior is encapsulated or the motors do not have special inner ventilation, a high thermal loading of the commutator brushes occurs since the brush holders are cooled exclusively by the hot inner air of the motor. This has been taken into consideration since an additional ventilation, for example, by a separate fan, in small size motors would reduce the extremely low volumes of such motors. These problems surface especially when the small motors are used for driving a blower for cooling of internal combustion engines of a motor vehicle, since in this case the electric motor is also exposed to the heat flow of the cooling medium circulation for the internal combustion engine.